Arena Raises $200M Series B at $3.1B Valuation, Nearly Doubling in 10 Months

Arena, the AI model ranking platform, said Thursday it raised a $200 million Series B round at a $3.1 billion valuation, up from $1.7 billion in January. The round was led by Lightspeed Venture Partners and Khosla Ventures, with Salesforce Ventures, 01 Advisors, Dell Technologies Capital, Endeavor Catalyst, a16z, Felicis and others participating. The company said it reached $100 million in annualized run-rate revenue in June, compared with $30 million at the time of its $150 million Series A. Arena, which began in 2023 as a UC Berkeley research project crowdsourcing AI model rankings, launched its commercial product, AI Evaluations, in September of last year, providing performance analytics to model labs and enterprises. The company also added an "alignment" leaderboard category ranking models on unauthorized actions, false attribution and "deceptive completion." OpenAI models currently top the preliminary alignment ranking.